Gas evolution behavior in aluminum electrolysis cell with vertical inert anode

doi:10.11949/j.issn.0438-1157.20161059

Abstract

Abstract:

The gas evolution is one of the key factors for alumina distribution in bath and current efficiency in aluminum electrolysis cell using vertical inert anodes. A see-through cell is presented to investigate the gas evolution and releasing behavior with big inert anode. The test results show that with small anode, the bubble behavior of nucleation, growth and detaching periodically occurs on surface of big anode. However, the sliding and coalescence behavior on big surface is different to that on small anode. At working face of the anode, however, multi layers of bubbles are formed. The bubbles adjacent to the anode are moving fast than those at the outer layer. Most of bubbles go directly into the atmosphere at the liquid surface, while the remaining bubbles are carried by the electrolyte to move horizontally and they are released gradually. There is a bubble foam layer on the electrolyte surface. The moving velocity of bubble generated at inert anode is measured by image processing, which is in the range of 0.006-0.445 m·s^-1. The bubbles at the bottom have a wide velocity range, while the bubbles at the middle have a narrow velocity range under the influence of the electrolyte.

Key words: bubble, electrolysis, flow, inert anode, releasing, coalescence

摘要：

垂直惰性阳极铝电解槽内，析气行为会影响氧化铝浓度分布和电流效率。利用新设计的透明电解槽进行了电解试验，观察了大尺寸惰性阳极气泡的析出及逸出过程。试验结果表明：在阳极底掌下，气泡进行周期性的生长、长大、并聚和脱离，但大尺寸阳极上气泡的滑动和并聚过程与小尺寸阳极上的不同。阳极工作面上则形成了气泡群，新形成的气泡迅速脱离。紧贴着阳极的气泡运行速度慢，外层的气泡运动速度快。所有气泡最终都经液面逸出，大部分气泡到达液面时立即逸出，少部分未及时逸出的气泡随着电解质做一段水平运动后才逐步逸出。测量到的惰性阳极的气泡运动速度为0.006~0.445 m·s^-1，底部的气泡运动速度分布范围宽，然而，受电解质的限制，中上部的范围窄。

关键词: 气泡, 电解, 流动, 惰性阳极, 逸出, 并聚

CLC Number:

TF821

ZHOU Yiwen, ZHOU Jiemin, CHEN Shouhui, YANG Jianhong, LIU Zhiming, BAO Shengzhong. Gas evolution behavior in aluminum electrolysis cell with vertical inert anode[J]. CIESC Journal, DOI: 10.11949/j.issn.0438-1157.20161059.

周益文, 周孑民, 陈首慧, 杨建红, 刘志明, 包生重. 垂直惰性阳极铝电解槽内的析气行为[J]. 化工学报, DOI: 10.11949/j.issn.0438-1157.20161059.

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